Mars Curiosity gets down to science

The left eye of the Mast Camera on NASA's Mars rover Curiosity took this image of the camera on the rover's arm, the Mars Hand Lens Imager (MAHLI), on Sept. 5. MAHLI is one of the tools on a turret at the end of the rover's robotic arm.

The image shows that MAHLI has a thin film or coating of Martian dust on it. This dust accumulated during Curiosity's final descent to the Martian surface, as the Mars Science Laboratory spacecraft's descent stage (or sky crane) engines were disrupting the surface nearby. The mechanism at the right in this image is Curiosity's
dust removal tool, a motorized wire brush.

I find these pictures really fascinating.
But there is one question, which leaves me no calm:
How such "Self portrait" could be physically taken when only single one (to my knowledge) robot exists on Mars?!
It looks like that photo made by standalone observer - no physical contact between camera and robot is visible on this picture.

I take it that this is more or less like taking two self-portraits; one with the right hand and one from the left, then cutting it apart and stitching together the two sides when each was not holding the camera.
It makes for a pretty interesting self-portrait and at first glance doesn't seem possible.

This is sooo coool. Science and human endeavor at its best.
Thanks for the coverage, George,
BTW, two lead engineers from Curiosity were on the NPR comedy program "Wait, Wait Don't Tell Me." Not only are they smart, they are funny!
http://www.npr.org/programs/wait-wait-dont-tell-me/